Guest post by Bob Tisdale
In advance of the UN negotiations next week in Cancun, the press and blogs today have included numerous elaborations on the UK Met Office press release Scientific evidence is Met Office focus at Cancun. The Australian article “Global temperature rises may be underestimated due to errors, Met Office study says” by Ben Webster includes the following statement, “The long-term rate of global warming was about 0.16C a decade in the 1970s, 1980s and 1990s but it slowed in the past 10 years to between 0.05C and 0.13C, depending on which of three major temperature records is used. The Met Office said that changes in the way ocean temperatures were measured had resulted in an under-estimate of about 0.03C in recent years.”
But what the Met Office fails to mention is that the dataset being discussed in the press release, their HADSST2 data, which is the sea surface temperature dataset used in their HADCRUT3 and HADCRUT3v global temperature products, is biased upwards by almost 0.12 deg C after 1998 due to a change in source data in 1998. I’ve illustrated and discussed this bias in two previous posts: Met Office Prediction: “Climate could warm to record levels in 2010” and The Step Change in HADSST Data After the 1997/98 El Nino.
The new source Sea Surface Temperature data was not fully consistent with the source dataset the Hadley Centre used prior to 1998. So when they merged the two datasets, the Hadley Centre failed to account for the inconsistency and created an upward bias in their HADSST2 data. This bias is easily seen when the other Hadley Centre sea surface temperature dataset, HADISST, is subtracted from the HADSST2 data, Figure 1. Note that the HADISST has relied primarily on satellite-based measurements since 1982, but the HADSST2 data is based on buoy and ship readings. The upward step is approximately 0.12 deg C. The bias created by the change in measurement methods over the past decade that was reported on in The Australian would only offset a portion of that shift.
http://i56.tinypic.com/308fjar.jpg
Figure 1
Hopefully, when the Hadley Centre finally releases its updated Sea Surface Temperature dataset (HADSST3) they will eliminate the upward step. And for those interested, here’s a link to a Met Office Scientific Advisory Committee (MOSAC) publication, “Climate monitoring and attribution,” that provides an overview of the upcoming HADSST3 and HADISST2 datasets. Refer to page 3 under the heading of “3. Progress in development of marine datasets.”
http://research.metoffice.gov.uk/research/nwp/publications/mosac/MOSAC_15.10.pdf
SOURCE
The HADSST2 and HADISST data used in this post are available through the KNMI Climate Explorer:
http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere
Posted by Bob Tisdale at 6:46 PM
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Thank Bob
I sincerely hope that the scientists without a real voice in Australia, will finally be given equal reporting in the Australian Media. Something that is sorely lacking. There is little balance at all. May your voices be heard and well understood above the political clamour.
“…eliminate the upward step”
Bob, let me guess how they will do this:
Lower the temps before 1998.
Raise the temps after 1998.
Result: Nice smooth “robust” upward trend, with no upward step.
How many more, “It’s word than we thought” cries can they credibly have?
Tom in Texas says:
November 26, 2010 at 8:01 pm
Getting hard not to be cynical isn’t it? I know, I feel the same way.
DaveE.
Professor David Karoly from The University of Melbourne was quoted in the Shepparton News (Victoria, Australia) on Nov 26 2010 as saying “Twenty-first century anthropogenic carbon dioxide emissions will contribute to warming and sea level rise for more than a millennium, due to the long timwscales required for removal of this gas”.
“He emphasised the fact that some 97 percent of the world’s climate scientists agreed with IPCC findings that, among many other things, suggested it was very likely that hot extremes, heat waves, and heavy precipitation events would continue to become more frequent.”
Liar liar pants on fire.
David Karoly is definitely off my christmas card list now.
Temperature. It seemed a rather simple concept in 9th grade science class.
I’m sure all this means something, but frankly it’s gone right over my head. Can some please explain the issue and the what the above means, vis a vis the Met claims, in simple english for us who only have 10 watt bulbs between our ears.
Thanks
I’m going to turn on the weather channel now and watch all the snow storms. Really I am. I hear the pacific northwest is going to get another blast of the white stuff this weekend. Seattle isn’t used to the frozen variety of precipitation.
Here is, how HadSST3 is being prepared:
************************
From: Tom Wigley
To: Phil Jones
Subject: Re: 1940s
Date: Sep 28, 2009
Cc: Ben Santer
Phil,
Here are some speculations on correcting SSTs to partly
explain the 1940s warming blip.
If you look at the attached plot you will see that the
land also shows the 1940s blip (as I’m sure you know).
So, if we could reduce the ocean blip by, say, 0.15 degC,
then this would be significant for the global mean — but
we’d still have to explain the land blip.
…
It would be good to remove at least part of the 1940s blip,
but we are still left with “why the blip”.
************************
I suppose they will eliminate the 1940 blip and considering the recent findings underestimating the global T, they will introduce another 0.12 °C into the late record.
We cannot expect from these people serious data. Canada recently dissolved their climate research center. Way to go!
@Confused:
The simple form is that the news is saying “It could be warmer than we thought because we made an error” while at the same time they are ignoring a larger error that makes it really cooler than they said in the first place. So the “warmers” are basically playing a game of ‘selective listening’ to potential errors.
@Michael:
It’s been a record early open at Vail Ski Resorts:
http://chiefio.wordpress.com/2010/11/27/record-early-skiing-and-snow/
Opened in the “November Teens” and with pre-Thanksgiving Skiing…
Yeah, a lot more snow on the way. It’s going to be this way for a few decades, so get used to it. The new cold PDO phase and all that…
Confused says:
November 26, 2010 at 10:36 pm
Hadley are splicing 2 sst data sets – mainly satellite data, pre 1998, and ships/buoys together, post 1998 that give different trends and different temperatures from pre-1998 data methods. They didn’t correct the data post 1998 that gives an upward bias to SST’s
And yesterday morning on BBC Radio 4 news it was reported that the Met Office have said that 2010 is on course to be the second warmest year on record. Considering winter2010 in the NH and winter 2010 in the SH which both broke cold records of one sort or another and the UK summer was not much to write home about one wonders which planet do these people live on.
Temperature readings of 0.03C are inside the error bands so how does this figure have any relevance? The Met. Office still insist on smoothing time series which is a serious error in statistical circles!
And in the meantime, the Met Office are announcing that 2010 is the hottest year ever (or at least not statistically different from 1998) – even though we are still a few weeks from the end of the year, and current temperatures are low (AQUA ch 5).
http://www.bbc.co.uk/news/uk-11841368
Irony is, the UK is suffering one of its coldest and snowiest ends to November in my lifetime, and is forecast to stay cold for up to a couple of weeks.
Is the HadSST data used in the construction of HadCRU3?
Bob that as an interesting discovery.
Some time ago I also found similar non-natural discontinuity between pre- and post-‘accurate instrument’ CET records.
http://www.vukcevic.talktalk.net/CET4a.htm
If this discontinuity indeed is an artefact of data standardisation before and after accurate measurements were available, then there is a serious consequence for the CETs trend, as I have shown here
http://www.vukcevic.talktalk.net/GWDa.htm
I wonder if the Met Office has just stopped caring about their credibility.
Even if their “extra 0.03ºC” ocean temperature was absolutely correct and they could measure to this accuracy, we are supposed to worry about 0.03ºC? Why??
These comedians know full well that the incompetent and venal politicians will latch on to their pronouncements and use them as justification of more hikes in tax and energy prices.
Sooner or later they will look out of the windows of their ivory tower and see the peasants massing with pitchforks and flaming torches. It will get much hotter for the Met Office scientists than any 0.03ºC!
Well would you ‘Adam and Eve’ it.
Just before it was beginning to look as though this year (Strong El Nino year) isn’t going to be any warmer than 1998 (The previous strong El Nino year) and therefore NOT the warmest year on record, those clever people at the Met Office have discovered yet another ‘trick’ to adjust 2010 upwards… and just in time for Cancun.
Confused says: “Can some please explain the issue and the what the above means…”
The Met Office claims that sea surface temperatures measured by buoys are lower than those measured by ships, and in the past 10 years, more buoys have been used to measure global sea surface temperatures. The additional use of buoys has caused them to report lower-than-actual sea surface temperature anomalies in their global surface temperature product, or so they say. Actually, I have no basis to doubt or contradict this. In fact, there are a number of papers that discuss this problem.
First, there are a number of Sea Surface Temperature datasets available for use in the global temperature products. The Hadley Centre, GISS, and NCDC all use different ones. Two of these datasets, the ones discussed in the post, are available from the Hadley Centre. The Met Office claim about buoy bias was for the dataset used in the Hadley Centre’s product, HADSST2, and it is based only on ship and buoy measurements. The other Hadley SST product has been based on satellite measurements since 1982. The following is a graph of those two global datasets from 1982 to present.
http://i53.tinypic.com/s4bfvk.jpg
A couple of years ago I noted that there was a curious difference between the Hadley Centre’s HADSST2 dataset and all other Sea Surface Temperature datasets. The HADSST2 data shifts up considerably during and after the spike in 1997/98. The spike in 1997/98 is due to an El Niño event and it masks the difference between the HADSST2 data and the others. Notice how that HADSST2 anomalies are below the HADISST data before the 1997/98 El Niño but are above it afterwards. The shift is easier to see if the HADISST data is shifted down 0.06 deg.
http://i51.tinypic.com/243nck5.jpg
In the graph I created for the post, Figure 1, I subtracted the HADISST data from the HADSST2 data to show the timing of the shift.
About 2 years ago, I discovered that the Hadley Centre changed sources for their HADSST2 data in 1998, while the sources for the other SST datasets remained constant. The supplier of the two datasets used by the Hadley Centre cautioned that there were inconsistencies between the two datasets, and it appears as though the Hadley Centre failed to account for those inconsistencies.
My point in this post was, before the Met Office can claim any importance from the bias created by the transition from ship measurements to buoys, they need to fix the upward shift created when they merged two incompatible SST datasets. The shift created by the use of the two incompatible datsets is considerably more than any bias caused by the change in measurement type.
P Wilson says: “Hadley are splicing 2 sst data sets – mainly satellite data, pre 1998, and ships/buoys together, post 1998 that give different trends and different temperatures from pre-1998 data methods. They didn’t correct the data post 1998 that gives an upward bias to SST’s”
Nope. Refer to my reply to Confused above.
The credibility of the Met Office in the UK is no longer an issue – it has none. I rubbed my eyes when I read earlier this week that 2010 would be the warmest year yet. Not in the bit of London where I live, it won’t. My outdoor max/min thermometers from which I keep a record, tell me its consistently below last year’s temps for this time of year.
The nonsense reason given by the head of the Met Ofice for this silliness will no doubt see the old temp records adjusted downward.
Nicley picked up!:
Juraj V. says:
November 26, 2010 at 11:41 pm
Here is, how HadSST3 is being prepared:
************************
From: Tom Wigley
To: Phil Jones
Subject: Re: 1940s
Date: Sep 28, 2009
Cc: Ben Santer
Bob,
did you notify Hadley about this error ?
If they really choose to ignore that step function, I wonder what is going on.
This is VERY interesting. Only two days ago I was looking at the Met. Office graph and noted the despite the short term ups and downs it seems fairly level before the el Nino event and equally flat after.
I had concluded that there had been some permanent effect and the temperatures had never recovered to the pre 1998 levels. That there was a step change around that time. I conjectured this may be similar to the step change in 1976 in the PDO cycle.
Basically I was HAD by Hadley !
Kudos many thanks and to Bob Tisdale for bringing this to light. I shall sleep a wiser man tonight.
I have just sent an e-mail message to the Met Office complaining about inaccurate weather forecasts. Yesterday I had to make a car journey from South Wales to Exeter (where, by coincidence, the Met Office is based). On Thursday night the weather forecasts on television were predicting snow for Scotland and parts of eastern England but not for South Wales and southwest England.
On Friday morning I checked the Met Office website before setting out but once again no snow was predicted for South Wales or southwest England. On the way back I had only got just over 30 miles from Exeter when a blizzard started. Conditions were even worse in South Wales with snow causing a 25 mile queue from the Severn Bridge toll booths onwards.
Now I don’t expect weather forecasts to be accurate all the time, but you would think the Met Office could predict blizzards over a large area several hours in advance. Only a couple of weeks ago the Met Office got a lot of criticism from people in Cornwall for failing to predict floods. (Cornwall is not far from the Met Office base in Exeter either).
Perhaps UK tax payers would prefer the Met Office to spend less of their money on global warming propaganda (sorry “research”) and more on its day job of weather forecasting.
If the present lot had been in charge of the Met Office in June 1944 they would have got the weather forecast for D-Day just as wrong as the Germans did and the landings would have been postponed and, since it would not have been possible to postpone them for very long, the Allies would have had to go ahead in much worse conditions, possibly with tragic consequences.
Three other great invasions failed largely due to the weather; the Mongol invasions of Japan in 1274 and 1281 failed when their fleets were destroyed by the “Divine Wind” or Kamikazi (hence the name of the Japanese suicide attacks on US and other Allied ships in World War II), and the Spanish Armada was greatly damaged by storms in 1588. That was also attributed to divine intervention. To celebrate the failure of the Armada the English made a commemorative medal saying ‘He blew with His winds, and they were scattered’.
If the Japanese and Mongols, and the English and Spanish, of those periods had thought like we do today the failure of those invasions would have been attributed to “climate change”!
Roy,
perhaps we also have divine intervention now that we have become too upity as a species, imagining that we have an undue influence on the world’s climate 😉
Actually we seem to have more than our fare share of forecasting ability in the UK. Not only do we have the Met Office, but Reading is home to the European Centre for Medium-Range Weather Forecasts, on whose weather modelling data much of Europe’s forecasting is based (e.g. here).
Manfred says: “did you notify Hadley about this error ?”
Nope.
Maybe buoys are more accurate than ships and they need to lower their ship based measurements to match the buoys? Notwithstanding this other really convenient failure to calibrate that Bob is pointing out.
After all, the buoys are scientific instruments design specifically to measure temperature as accurately as possible. Ships are not.
If they had any integrity whatsoever, why use the non-scientific instrument over the specially designed scientific instrument, just because doing so happens to bias the temperatures the way you need them to be biased?